Displaying publications 1 - 20 of 44 in total

  1. Rosli R, Abdul Kadir MR, Kamarul T
    Proc Inst Mech Eng H, 2014 Apr;228(4):342-9.
    PMID: 24622982 DOI: 10.1177/0954411914527074
    Anterior corpectomy and reconstruction using a plate with locking screws are standard procedures for the treatment of cervical spondylotic myelopathy. Although adding more screws to the construct will normally result in improved fixation stability, several issues need to be considered. Past reports have suggested that increasing the number of screws can result in the increase in spinal rigidity, decreased spine mobility, loss of bone and, possibly, screw loosening. In order to overcome this, options to have constrained, semi-constrained or hybrid screw and plate systems were later introduced. The purpose of this study is to compare the stability achieved by four and two screws using different plate systems after one-level corpectomy with placement of cage. A three-dimensional finite-element model of an intact C1-C7 segment was developed from computer tomography data sets, including the cortical bone, soft tissue and simulated corpectomy fusion at C4-C5. A spinal cage and an anterior cervical plate with different numbers of screws and plate systems were constructed to a fit one-level corpectomy of C5. Moment load of 1.0 N m was applied to the superior surface of C1, with C7 was fixed in all degrees of freedom. The kinematic stability of a two-screw plate was found to be statistically equivalent to a four-screw plate for one-level corpectomy. Thus, it can be a better option of fusion and infers comparable stability after one-level anterior cervical corpectomy, instead of a four-screw plate.
  2. Li S, Shaharudin S, Abdul Kadir MR
    Am J Phys Med Rehabil, 2021 04 01;100(4):337-344.
    PMID: 33727516 DOI: 10.1097/PHM.0000000000001567
    BACKGROUND: Due to the pain caused by knee injuries, low-load resistance training with blood flow restriction (L-BFR) may be a potential adjuvant therapeutic tool in the rehabilitation of knee injuries. This review aimed to analyze the effectiveness of L-BFR training modality in knee rehabilitation.

    DESIGN: A meta-analysis was conducted to determine the potential impact of blood flow restriction on patients with knee injuries. PubMed, EBSCO, and Web of Science databases were searched for eligible studies from January 2000 until January 2020. The mean differences of the data were analyzed using Revman 5.3 software with a 95% confidence interval.

    RESULTS: Nine studies fulfilled the inclusion criteria. These studies involved 179 patients who received L-BFR, 96 patients who underwent high-load resistance training, and another 94 patients who underwent low-load resistance training. The analysis of pooled data showed that patients in both the L-BFR (standardized mean difference, 0.83 [0.53, 1.14], P < 0.01) and high-load resistance training (standardized mean difference, -0.09 [-0.43, 0.24], P = 0.58) groups experienced an increase in muscle strength after the training. In addition, pain score was significantly reduced in the L-BFR group compared with the other two groups (standardized mean difference, -0.61 [-1.19, -0.03], P = 0.04).

    CONCLUSIONS: Muscle strength increased after L-BFR and high-load resistance training compared with low-load resistance training. Furthermore, pain score was significantly reduced after L-BFR. Hence, L-BFR is a potential intervention to be applied in rehabilitation of knee injuries.

  3. Darmawan MF, Yusuf SM, Abdul Kadir MR, Haron H
    Leg Med (Tokyo), 2015 Mar;17(2):71-8.
    PMID: 25456051 DOI: 10.1016/j.legalmed.2014.09.006
    Age estimation was used in forensic anthropology to help in the identification of individual remains and living person. However, the estimation methods tend to be unique and applicable only to a certain population. This paper analyzed age estimation using twelve regression models carried out on X-ray images of the left hand taken from an Asian data set for subjects under the age of 19. All the nineteen bones of the left hand were measured using free image software and the statistical analysis were performed using SPSS. There are two methods to determine age in this study which are single bone method and all bones method. For single bone method, S-curve regression model was found to have the highest R-square value using second metacarpal for males, and third proximal phalanx for females. For age estimation using single bone, fifth metacarpal from males and fifth proximal phalanx from females can be used due to the lowest mean square error (MSE) value. To conclude, multiple linear regressions is the best techniques for age estimation in cases where all bones are available, but if not, S-curve regression can be used using single bone method.
  4. Syahrom A, Abdul Kadir MR, Harun MN, Öchsner A
    Med Eng Phys, 2015 Jan;37(1):77-86.
    PMID: 25523865 DOI: 10.1016/j.medengphy.2014.11.001
    Artificial bone is a suitable alternative to autografts and allografts, however their use is still limited. Though there were numerous reports on their structural properties, permeability studies of artificial bones were comparably scarce. This study focused on the development of idealised, structured models of artificial cancellous bone and compared their permeability values with bone surface area and porosity. Cancellous bones from fresh bovine femur were extracted and cleaned following an established protocol. The samples were scanned using micro-computed tomography (μCT) and three-dimensional models of the cancellous bones were reconstructed for morphology study. Seven idealised and structured cancellous bone models were then developed and fabricated via rapid prototyping technique. A test-rig was developed and permeability tests were performed on the artificial and real cancellous bones. The results showed a linear correlation between the permeability and the porosity as well as the bone surface area. The plate-like idealised structure showed a similar value of permeability to the real cancellous bones.
  5. Jamuna-Thevi K, Saarani NN, Abdul Kadir MR, Hermawan H
    Mater Sci Eng C Mater Biol Appl, 2014 Oct;43:253-63.
    PMID: 25175212 DOI: 10.1016/j.msec.2014.07.028
    This paper discusses the successful fabrication of a novel triple-layered poly(lactic-co-glycolic acid) (PLGA)-based composite membrane using only a single step that combines the techniques of solvent casting and thermally induced phase separation/solvent leaching. The resulting graded membrane consists of a small pore size layer-1 containing 10 wt% non-stoichiometric nanoapatite (NAp)+1-3 wt% lauric acid (LA) for fibroblastic cell and bacterial inhibition, an intermediate layer-2 with 20-50 wt% NAp+1 wt% LA, and a large pore size layer-3 containing 30-100 wt% NAp without LA to allow bone cell growth. The synergic effects of 10-30 wt% NAp and 1 wt% LA in the membrane demonstrated higher tensile strength (0.61 MPa) and a more elastic behavior (16.1% elongation at break) in 3 wt% LA added membrane compared with the pure PLGA (0.49 MPa, 9.1%). The addition of LA resulted in a remarkable plasticizing effect on PLGA at 3 wt% due to weak intermolecular interactions in PLGA. The pure and composite PLGA membranes had good cell viability toward human skin fibroblast, regardless of LA and NAp contents.
  6. Fallahiarezoodar A, Abdul Kadir MR, Alizadeh M, Naveen SV, Kamarul T
    Knee Surg Sports Traumatol Arthrosc, 2014 Dec;22(12):3019-27.
    PMID: 25149643 DOI: 10.1007/s00167-014-3227-7
    PURPOSE: Reproducing the femoral rollback through specially designed mechanism in knee implants is required to achieve full knee function in total knee arthroplasty. Most contemporary implants use cam/post mechanism to replace the function of Posterior Cruciate Ligament. This study was aimed to determine the most appropriate cam and post designs to produce normal femoral rollback of the knee.

    METHODS: Three different cams (triangle, ellipse, and circle) and three different posts (straight, convex, concave) geometries were considered in this study and were analysed using kinematic analyses. Femoral rollback did not occur until reaching 50° of knee flexion. Beyond this angle, two of the nine combinations demonstrate poor knee flexion and were eliminated from the study.

    RESULTS: The combination of circle cam with concave post, straight post and convex post showed 15.6, 15.9 and 16.1 mm posterior translation of the femur, respectively. The use of ellipse cam with convex post and straight post demonstrated a 15.3 and 14.9 mm femoral rollback, whilst the combination of triangle cam with convex post and straight post showed 16.1 and 15.8 mm femoral rollback, respectively.

    CONCLUSION: The present study demonstrates that the use of circle cam and convex post created the best femoral rollback effect which in turn produces the highest amount of knee flexion. The findings of the study suggest that if the design is applied for knee implants, superior knee flexion may be possible for future patients.


  7. Saidin S, Chevallier P, Abdul Kadir MR, Hermawan H, Mantovani D
    Mater Sci Eng C Mater Biol Appl, 2013 Dec 1;33(8):4715-24.
    PMID: 24094179 DOI: 10.1016/j.msec.2013.07.026
    Hydroxyapatite (HA) coated implant is more susceptible to bacterial infection as the micro-structure surface which is beneficial for osseointegration, could also become a reservoir for bacterial colonisation. The aim of this study was to introduce the antibacterial effect of silver (Ag) to the biomineralised HA by utilising a polydopamine film as an intermediate layer for Ag and HA immobilisation. Sufficient catechol groups in polydopamine were required to bind chemically stainless steel 316 L, Ag and HA elements. Different amounts of Ag nanoparticles were metallised on the polydopamine grafted stainless steel by varying the immersion time in silver nitrate solution from 12 to 24 h. Another polydopamine layer was then formed on the metallised film, followed by surface biomineralisation in 1.5 Simulated Body Fluid (SBF) solution for 3 days. Several characterisation techniques including X-Ray Photoelectron Spectroscopy, Atomic Force Microscopy, Scanning Electron Microscopy and Contact Angle showed that Ag nanoparticles and HA agglomerations were successfully immobilised on the polydopamine film through an element reduction process. The Ag metallisation at 24 h has killed the viable bacteria with 97.88% of bactericidal ratio. The Ag was ionised up to 7 days which is crucial to prevent bacterial infection during the first stage of implant restoration. The aged functionalised films were considered stable due to less alteration of its chemical composition, surface roughness and wettability properties. The ability of the functionalised film to coat complex and micro scale metal make it suitable for dental and orthopaedic implants application.
  8. Ahmad M, Uzir Wahit M, Abdul Kadir MR, Mohd Dahlan KZ
    ScientificWorldJournal, 2012;2012:474851.
    PMID: 22666129 DOI: 10.1100/2012/474851
    Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA) as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudability. The mechanical and bioactive properties were improved with incorporation of HA. Inclusion of HA from 10 to 50 phr resulted in a progressive increase in flexural strength and modulus of the composites. The strength increment is due to the improvement on surface contact between the irregular shape of HA and polymer matrix by formation of mechanical interlock. The HA particles were homogenously distributed even at higher percentage showed improvement in wetting ability between the polymer matrix and HA. The inclusion of HA enhanced the bioactivity properties of the composite by the formation of calcium phosphate (Ca-P) precipitates on the composite surface as proven from SEM and XRD analysis.
  9. Saidin S, Abdul Kadir MR, Sulaiman E, Abu Kasim NH
    J Dent, 2012 Jun;40(6):467-74.
    PMID: 22366313 DOI: 10.1016/j.jdent.2012.02.009
    The aim of this study was to analyse micromotion and stress distribution at the connections of implants and four types of abutments: internal hexagonal, internal octagonal, internal conical and trilobe.
  10. Bajuri MN, Abdul Kadir MR, Murali MR, Kamarul T
    Med Biol Eng Comput, 2013 Feb;51(1-2):175-86.
    PMID: 23124814 DOI: 10.1007/s11517-012-0982-9
    The total replacement of wrists affected by rheumatoid arthritis (RA) has had mixed outcomes in terms of failure rates. This study was therefore conducted to analyse the biomechanics of wrist arthroplasty using recently reported implants that have shown encouraging results with the aim of providing some insights for the future development of wrist implants. A model of a healthy wrist was developed using computed tomography images from a healthy volunteer. An RA model was simulated based on all ten general characteristics of the disease. The ReMotion ™ total wrist system was then modelled to simulate total wrist arthroplasty (TWA). Finite element analysis was performed with loads simulating the static hand grip action. The results show that the RA model produced distorted patterns of stress distribution with tenfold higher contact pressure than the healthy model. For the TWA model, contact pressure was found to be approximately fivefold lower than the RA model. Compared to the healthy model, significant improvements were observed for the TWA model with minor variations in the stress distribution. In conclusion, the modelled TWA reduced contact pressure between bones but did not restore the stress distribution to the normal healthy condition.
  11. Ishak MI, Abdul Kadir MR, Sulaiman E, Abu Kasim NH
    Int J Oral Maxillofac Surg, 2012 Sep;41(9):1077-89.
    PMID: 22575179 DOI: 10.1016/j.ijom.2012.04.010
    The aim of this study was to compare two different types of surgical approaches, intrasinus and extramaxillary, for the placement of zygomatic implants to treat atrophic maxillae. A computational finite element simulation was used to analyze the strength of implant anchorage for both approaches in various occlusal loading locations. Three-dimensional models of the craniofacial structures surrounding a region of interest, soft tissue and framework were developed using computed tomography image datasets. The implants were modelled using computer-aided design software. The bone was assumed to be linear isotropic with a stiffness of 13.4 GPa, and the implants were assumed to be made of titanium with a stiffness of 110 GPa. Masseter forces of 300 N were applied at the zygomatic arch, and occlusal loads of 150 N were applied vertically onto the framework surface at different locations. The intrasinus approach demonstrated more satisfactory results and could be a viable treatment option. The extramaxillary approach could also be recommended as a reasonable treatment option, provided some improvements are made to address the cantilever effects seen with that approach.
  12. Syahrom A, Abdul Kadir MR, Abdullah J, Öchsner A
    Med Eng Phys, 2013 Jun;35(6):792-9.
    PMID: 22959618 DOI: 10.1016/j.medengphy.2012.08.011
    In the development of artificial cancellous bones, two major factors need to be considered: the integrity of the overall structure and its permeability. Whilst there have been many studies analysing the mechanical properties of artificial and natural cancellous bones, permeability studies, especially those using numerical simulation, are scarce. In this study, idealised cancellous bones were simulated from the morphological indices of natural cancellous bone. Three different orientations were also simulated to compare the anisotropic nature of the structure. Computational fluid dynamics methods were used to analyse fluid flow through the cancellous structures. A constant mass flow rate was used to determine the intrinsic permeability of the virtual specimens. The results showed similar permeability of the prismatic plate-and-rod model to the natural cancellous bone. The tetrakaidecahedral rod model had the highest permeability under simulated blood flow conditions, but the plate counterpart had the lowest. Analyses on the anisotropy of the virtual specimens showed the highest permeability for the horizontal orientation. Linear relationships were found between permeability and the two physical properties, porosity and bone surface area.
  13. Syahrom A, Abdul Kadir MR, Abdullah J, Öchsner A
    Med Biol Eng Comput, 2011 Dec;49(12):1393-403.
    PMID: 21947767 DOI: 10.1007/s11517-011-0833-0
    The relationship between microarchitecture to the failure mechanism and mechanical properties can be assessed through experimental and computational methods. In this study, both methods were utilised using bovine cadavers. Twenty four samples of cancellous bone were extracted from fresh bovine and the samples were cleaned from excessive marrow. Uniaxial compression testing was performed with displacement control. After mechanical testing, each specimen was ashed in a furnace. Four of the samples were exemplarily scanned using micro-computed tomography (μCT) and three dimensional models of the cancellous bones were reconstructed for finite element simulation. The mechanical properties and the failure modes obtained from numerical simulations were then compared to the experiments. Correlations between microarchitectural parameters to the mechanical properties and failure modes were then made. The Young's modulus correlates well with the bone volume fraction with R² = 0.615 and P value 0.013. Three different types of failure modes of cancellous bone were observed: oblique fracture (21.7%), perpendicular global fracture (47.8%), and scattered localised fracture (30.4%). However, no correlations were found between the failure modes to the morphological parameters. The percentage of error between computer predictions and the actual experimental test was from 6 to 12%. These mechanical properties and information on failure modes can be used for the development of synthetic cancellous bone.
  14. Abdullah MR, Goharian A, Abdul Kadir MR, Wahit MU
    J Biomed Mater Res A, 2015 Nov;103(11):3689-702.
    PMID: 25856801 DOI: 10.1002/jbm.a.35480
    The use of polyetheretherketone (PEEK) composites in the trauma plating system, total replacement implants, and tissue scaffolds has found great interest among researchers. In recent years (2008 afterward), this type of composites has been examined for suitability as substitute material over stainless steel, titanium alloys, ultra high molecular weight polyethylene, or even biodegradable materials in orthopedic implant applications. Biomechanical and bioactivity concepts were contemplated for the development of PEEK orthopedic implants and a few primary clinical studies reported the clinical outcomes of PEEK-based orthopedic implants. This study aims to review and discuss the recent concepts and contribute further concepts in terms of biomechanical and bioactivity challenges for the development of PEEK and PEEK composites in orthopedic implants.
  15. Almasi D, Izman S, Sadeghi M, Iqbal N, Roozbahani F, Krishnamurithy G, et al.
    Int J Biomater, 2015;2015:475435.
    PMID: 25838826 DOI: 10.1155/2015/475435
    Polyether ether ketone (PEEK) is considered the best alternative material for titanium for spinal fusion cage implants due to its low elasticity modulus and radiolucent property. The main problem of PEEK is its bioinert properties. Coating with hydroxyapatite (HA) showed very good improvement in bioactivity of the PEEK implants. However the existing methods for deposition of HA have some disadvantages and damage the PEEK substrate. In our previous study a new method for deposition of HA on PEEK was presented. In this study cell proliferation of mesenchymal stem cell and apatite formation in simulated body fluid (SBF) tests were conducted to probe the effect of this new method in improvement of the bioactivity of PEEK. The mesenchymal stem cell proliferation result showed better cells proliferation on the treated layer in comparison with untreated PEEK. The apatite formation results showed the growth of the HA on the treated PEEK but there was not any sight of the growth of HA on the untreated PEEK even after 2 weeks. The results showed the new method of the HA deposition improved the bioactivity of the treated PEEK in comparison with the bare PEEK.
  16. Ramlee MH, Beng GK, Bajuri N, Abdul Kadir MR
    Med Biol Eng Comput, 2018 Jul;56(7):1161-1171.
    PMID: 29209961 DOI: 10.1007/s11517-017-1762-3
    The provision of the most suitable rehabilitation treatment for stroke patient remains an ongoing challenge for clinicians. Fully understanding the pathomechanics of the upper limb will allow doctors to assist patients with physiotherapy treatment that will aid in full arm recovery. A biomechanical study was therefore conducted using the finite element (FE) method. A three-dimensional (3D) model of the human wrist was reconstructed using computed tomography (CT)-scanned images. A stroke model was constructed based on pathological problems, i.e. bone density reductions, cartilage wane, and spasticity. The cartilages were reconstructed as per the articulation shapes in the joint, while the ligaments were modelled using linear links. The hand grip condition was mimicked, and the resulting biomechanical characteristics of the stroke and healthy models were compared. Due to the lower thickness of the cartilages, the stroke model reported a higher contact pressure (305 MPa), specifically at the MC1-trapezium. Contrarily, a healthy model reported a contact pressure of 228 MPa. In the context of wrist extension and displacement, the stroke model (0.68° and 5.54 mm, respectively) reported a lower magnitude than the healthy model (0.98° and 9.43 mm, respectively), which agrees with previously reported works. It was therefore concluded that clinicians should take extra care in rehabilitation treatment of wrist movement in order to prevent the occurrence of other complications. Graphical abstract ᅟ.
  17. Ramlee MH, Seng GH, Ros Felip A, Abdul Kadir MR
    Injury, 2021 Aug;52(8):2131-2141.
    PMID: 33745700 DOI: 10.1016/j.injury.2021.03.017
    An external fixator is a promising medical device that could provide optimum stability and reduce the rate of complications in treating bone fracture during intervention period. It is noted that the biomechanics behaviour of device can be altered by introducing more features such as material suitability and additional components. Therefore, this study was conducted via finite element method to investigate the effects of additional hollow cylinder coated with external fixator screws in treating Type III pilon fracture. Finite element models which have been validated with experimental data were used to simulate stresses at the pin-bone interface and relative micromovement at interfragmentary fractures during swing (70 N load) and stance phases (350 N load). All bones and external fixators were assigned with isotropic material properties while the cartilages were simulated with hyper-elastic. For the hollow cylinder, polyethylene was assigned due to its properties which are equivalent to the bone. From the results, it is found that stresses at the pin-bone interface for the coated screws were reduced to 54% as compared to the conventional fixator. For the micromovement, there was no difference between both models, whereby the value was 0.03 mm. The results supported previously published literature, in which high stresses are unavoidable at the interface, fortunately, those stresses did not exceed the ultimate strength of bone, which is safe for treating patients. In conclusion, if patients are allowed to bear weight bearing, the external fixator with coated screws is a more favourable option to be fixed into the bone to avoid complications at the interface.
  18. Bakhsheshi-Rad HR, Hamzah E, Kasiri-Asgarani M, Jabbarzare S, Iqbal N, Abdul Kadir MR
    Mater Sci Eng C Mater Biol Appl, 2016 Mar;60:526-537.
    PMID: 26706560 DOI: 10.1016/j.msec.2015.11.057
    The present study addressed the synthesis of a bi-layered nanostructured fluorine-doped hydroxyapatite (nFHA)/polycaprolactone (PCL) coating on Mg-2Zn-3Ce alloy via a combination of electrodeposition (ED) and dip-coating methods. The nFHA/PCL composite coating is composed of a thick (70-80 μm) and porous layer of PCL that uniformly covered the thin nFHA film (8-10 μm) with nanoneedle-like microstructure and crystallite size of around 70-90 nm. Electrochemical measurements showed that the nFHA/PCL composite coating presented a high corrosion resistance (R(p)=2.9×10(3) kΩ cm(2)) and provided sufficient protection for a Mg substrate against galvanic corrosion. The mechanical integrity of the nFHA/PCL composite coatings immersed in SBF for 10 days showed higher compressive strength (34% higher) compared with the uncoated samples, indicating that composite coatings can delay the loss of compressive strength of the Mg alloy. The nFHA/PCL coating indicted better bonding strength (6.9 MPa) compared to PCL coating (2.2 MPa). Immersion tests showed that nFHA/PCL composite-coated alloy experienced much milder corrosion attack and more nucleation sites for apatite compared with the PCL coated and uncoated samples. The bi-layered nFHA/PCL coating can be a good alternative method for the control of corrosion degradation of biodegradable Mg alloy for implant applications.
  19. Ulum MF, Arafat A, Noviana D, Yusop AH, Nasution AK, Abdul Kadir MR, et al.
    Mater Sci Eng C Mater Biol Appl, 2014 Mar 1;36:336-44.
    PMID: 24433920 DOI: 10.1016/j.msec.2013.12.022
    Biodegradable metals such as magnesium, iron and their alloys have been known as potential materials for temporary medical implants. However, most of the studies on biodegradable metals have been focusing on optimizing their mechanical properties and degradation behavior with no emphasis on improving their bioactivity behavior. We therefore investigated the possibility of improving iron biodegradation rate and bioactivity by incorporating various bioactive bioceramics. The iron-based bioceramic (hydroxyapatite, tricalcium phosphate and biphasic calcium phosphate) composites were prepared by mechanical mixing and sintering process. Degradation studies indicated that the addition of bioceramics lowered the corrosion potential of the composites and slightly increased their corrosion rate compared to that of pure iron. In vitro cytotoxicity results showed an increase of cellular activity when rat smooth muscle cells interacted with the degrading composites compared to pure iron. X-ray radiogram analysis showed a consistent degradation progress with that found in vivo and positive tissue response up to 70 days implantation in sheep animal model. Therefore, the iron-based bioceramic composites have the potential to be used for biodegradable bone implant applications.
  20. Hussain F, Abdul Kadir MR, Zulkifly AH, Sa'at A, Aziz AA, Hossain G, et al.
    Biomed Res Int, 2013;2013:175056.
    PMID: 24294597 DOI: 10.1155/2013/175056
    The distal femurs of 100 subjects (50 men, 50 women) from the Malay population aged between 19 and 38 years were scanned to measure the anterior-posterior (AP) and medial-lateral (ML) width. The mean AP values were 64.02 ± 3.38 mm and 57.33 ± 3.26 mm for men and women, respectively, and the mean ML values were 74.91 ± 3.52 mm and 64.53 ± 3.07 mm. We compared our data to that published previously for the Chinese and Indian populations. It was found that the Malay population had smaller distal femur than that of the Chinese but was larger than that of the Indian population (P < 0.05). In conclusion, although it is well established that Asians have a smaller distal femur size than that of the Western population, the variations in different Asian ethnicities may need to be considered when designing the appropriate knee implant.
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